Abstract: Three mixing section configurations, i.e. doubleflight, hake, and tripleflight were magnified to two and ten times according to geometric similarity principle, respectively. Polyflow software was employed to simulate the flow field in different mixing sections. Mean pressure and mixing index of different channel crosssections during one revolution period, residence time distribution, cumulative probability distribution of depolymerization power density, and modified Lyapunov index on the exit of mixing section, specific energy, torque, and axial force were used as evaluating index to analyze the effects of geometric similarity scaleup on mixing section's flow field feature, mixing quality, energy cost, etc. In these simulations, the rotational speed of rotors kept constant while the volume flow rate of mixing section inlet increased by the geometric scaleup ratio′s cube. Simulation showed that after being magnified to different size according to geometric similarity principle, the primary features of flow field, mixing effect and specific energy of mixing section were similar to those of corresponding prototypes, while torque and axial force increased by the square and cube of the geometric scaleup ratio, respectively. In the further study, similarity of the heat equilibrium should be considered to guarantee the similar plasticization effect.

Key words: two-rotor continuous mixer, mixing section configuration, geometric similar scale-up rule, flow field simulation